Water-tube steam boileb



Re. 18,901 3 Sheets-Sheet 2 E. J. FRANKLIN WATER TUBE STEAM BOILER July25, 1933.

Original Filed July 7. 1925 n M m T A INVENTOR.

m M m F, J 4 W a. f

posed to combustion chamber.

Reissued July 25, 1933 UNI ED- STATES T Re. 18,901

PATENT OFFICE EDWARD J; FRANKLIN, or SALT LAKE CITY, UTAH I WATER-TUBE)STEAM. BOILER Original No. 1,634,139, dated June 28, 1927, Serial No.filed October 2,1931.

This invention relates to water tube steam boilers, and more especiallyto a novel arrangement of boiler and rear or brldge wall are to expose agreater tube surface to the radiant heat of the furnace; to eliminatethe necessity of a fire brick bridge wall; to pro-. vide maximumcombustion space with given boiler setting dimensions; to provide a moresuitable pocket or chamber for the collectlon and easy disposal of ash,flue dust or soot which may collect from the back passes; to

increase the circulation of water in the boiler, V and especially in thelowest row of tubes and thus prevent deposition of scale or sed mentwith the resultant failure of tubes; to protect the furnace brick workboth by direct screening effect of back. and side walls and by reiducing the heat in the combustion chamber; to reduce furnace maintenancecosts by eliminating large fire brick bridge walls commonly in use, andby reducing furnace temperatures due to increased radiant heatingsurface ex- The invention is particularly applicable to the straighttube type of boilers such as the Heine, Babcock & Wilcox,- Edgemoor andCase -Hedges steam boilers, but is also applica le with certainmodifications to other types of water tubes such as the bent tubeboilers of Stirling or similar types.

The accompanying drawings illustrate embodiments of my invention andreferring thereto: Figure 1 is a longitudinal section of a.

straight tube boiler provided with my improved water tube bridge wallbaflie. v

Fig. 2 is a section on line 22 in Fig. 1,

my with part of the frontheader broken away.

Fig. 3 is a section on line 33 in Fig. 1.

Fig. 4' is a section on line 4:l in Fig. 1.

Fig. 5' is a view similarto Fig. 1 showing the application of theinvention to a straight 43'? tube boiler of a somewhat difierentconstruction. I 1

Fig. 6 is a partial section showing a different location of the watercirculating system for the lower row of tubes. I

- ,Fig. 7 .is a longitudinal sectionof a bent The main objects of theinvention 7 Serial No. 566,542.

tube boiler'provided with a bridge wall baflle according to myinvention.

Fig. '8 is a section on line 8 8 in Fig. 7. Referring to Figs. 1 and 2the steam boiler therein shown comprises a series or bank of 41,963,filed July 7, 1925. Application for reissue water tubes 1 connected toforward and rear headers 2 and 3 which are also connected to the steamdrums 4. The usual meansare provided for drawing off steam from thesteam ing' from the fire-box to the stack and 'de-' fiect such gas so asto cause same to pass several times between the water tubes in wellknown manner. The baffle plate 10 may be arranged in accordance with'theusual practice, preferably inclined or obliquely extending from' nearlythe top'of the water tubes toithe bottom thereof in a downward andrearward direction and according to my invention a supplementary oradditional baffie means 16is provided, preferably in line withj thisbaflle plate 10, and formed of firebrick, iron or'other suitablerefractory material supported and protected by water tubes ashereinafter described.

In applying my invention to a boiler of the straight tube type I preferto bend the lower row of tubes indicated at 1' downwardly where theyapproach the inclined baffie plate 10 and to extend said tubes inoblique downward direction to the rear end of,

Said downwardly bent por the fire-box. tions may extend at any suitableangle, for

example at an angle'of from 30 to 75 tothe horizontal. In the form shownthe rearv portions of these tubes are bent at an angle of approximately45 to their front portions and to the remaining tubes. As shown in thedrawings, said boiler tubes '1 may extend through the rear wall of thefire box and be connected to a lower header 12 outside andimmediatelyadjacent the rear wall 19 of the furnace. Said lower header may beconnected at its ends by pipes 13 extending either inside or outside ofthe furnace walls to an upper header 14 Which is "connected bypipes '15to the rear header or Water leg 3 of the steam boiler. Baffle means 16consisting for'exa'mpleof'plates or slabs of refractory materialindicated at 17 are arranged back of and overlyingahe obliquerportionsof water tubes 1 so that said vb aflle means are" supported by suchwater tubes and are protected by the water tubes to'a large extent fromthe heat of the combus-' tion chamber. The upper and lowerheaders 14511C112 may be provided with Ts 18 where they areconnected to the pipes13 to facili-. tate cleaning of theseheaders, the outeropening ofsaid Tsbeing plugged'in normal operation.-:&:Suitable blowoif'means 40 may alsobe 'providedat the ends of the lower header. I The baflle wall 16cooperateswith the rear wall19 of the furnace to form a pocket 20 for vthe collection of ashes,soot, dust,-etc., from" the back passes, and" a'suitable means maybe- 7 provided for permitting access to said, pocket:

1 from, for example an access opening 20 with or; forremoval ofcollected material th,ere-' door.-22.

The: construction of" the boiler shown in Fig. 5- isisubstantiallythesame" as that above 7 described with ,the exceptionlthat the drumis-located-at the rear of. the boiler setting and; extendstransverselywith respect to the tubes andis connected to the front header 2 by meansof pipes 23.- I have also shown the short pipes 15 connecting the header14' to ithe watersleg 3' as bein'gQbent at right angles inthiscase','although either the straight or bent 'form'iof connectingypipe isadaptable to either typeof'boiler construction. w

' In the operation of the boilers above de;

tscribedfuel and air are admitted through burner means '7 andcombustion; takes place in -'the'combustio'n chamber 6. "It may be notedthat'by forming the bridge wallbafile as substantially a continuation-ofthe bafiie 10 :and carrying it downwardly and rearwardly a largercombustion chamber -:i's provided 1 than is the case in the usu'altype'of construction in which a fire brick bridge wall is pro videdextending vertically downward from -Tthe lowerjend of bafile 10, that isapproxi mately from the position of the upper end of: the bridge :wallbafllelG of my invention; By-A-means of 'myimproved' construction asubstantially unobstructed combustion chamber isprovid'ed extendingfrom-the frontwall 1 1 of the furnace to the rear wall 19;- The Iprovision of such'a'large unobstructed'combustionchamber i'sof'particular advantagev in connection with the burning of liquid, 7iga'seous, or powldere'd fuel, as it permits more complete combustion ofsuch fuel therein.

The hot products of combustion pass up. over a the upper edge of bafile10, down between baffles 10 and 9, and thenceout to the stack outlet 8,giving up their heat to the water tubes in their passage to heat'thewater therein. The lower row oftubes 1 are exposed to the mostintenseheat and particularly the inclined portions thereof in front of thebaffies 16. In addition to heat received directly from the hot gases,these tubes are exposed to radiation of heat from the hot walls of thecombustion chamber and .also take up heat received byradiation onto thebasis 16' with which such tubes are in contact at their inclinedportions. The rapid heating of. the water thusv produced in these tubescauses an extremely good circulation of water therein and not onlyproduces an efiicient utilization of the heat but also preventsdeposition of the scale or sediment in the tubes. The

direction of circulationof water is downward in the connecting pipes 13and upward in the tubes 1. j The tubes 1 being directly connected withthe boiler improve the entire circulation therein. I

,7 T he reception of a considerable amount of heat by radiation ontothese tubes'cools the combustion chamber-somewhat below the temperatureproduced in the ordinary type of boiler in whichthecombustion chamber isalmostentirely surrounded by fire brick and thus protects, the furnacebrickwork.

F urthermore the inclined portions of the tubes 1 serve to protect thebrick or refractory plates 1'7 both direct screening action and bytaking up heattherefrom. In addition to the above advantageous featuresthe elimination of the fire brick bridge wall now usedinitselfmateriallv reduces the 'cost'of maintenance ofthe, furnaces.

-Any soot,dust,or ashes collecting above the baflle 10 or the bridgewall bafile 16'settles tothe bottom ofpocketj 20 and may be easilyremoved from time to time'by removingdoor 22 and cleaning out thecollected material through the opening 21. In the ordinary type of"Water tube boiler any solid ma'-- terial deposited in the back passescollects betweenthe tubes and is very difiicultly removed. Byjprovidingthe lower-most row of tubes,- according to my invention, with,

. portions extending clear" of and below the other :tubes and providinga wall of refractory material on such portions of these tubes, a readilyaccessible andeasily cleaned pocket is provided between said wall ofrefractory material and the rear wall "of the furnace,"

into which such deposited"solidmaterial falls andfrom which it may beremoved easily;

While Iprefer, for the sake of. convenience and superior construction,to locate the lower header 12 outside the'rear wall of the furnace asabove described, it may in some cases be located inside, but immediatelyadia cent-the lected material.

rear wall, as shown in Fig.6; Insu'ch case the lower-tubes? do notextend through the rear wall but header 12 extends through the sidewalls for'connection. to nines In order to facilitate the cleaning ametalplate 24 may be provided over the header 12.

i As shownin Figs. 7 and S-the: bridge wall baflie'according to'myinvention may also be applied in connection with boilers-of the benttube type such as the Stirling boiler. The boilershown in these figurescomprises the usual steam, water and mud drums 25, 26, 27 and 28connected in the usual manner by banks of tubes indicated at 29, 30,31,32 and 33, and provided with the usual means for feeding waterthereto and permitting with drawal ofsteam therefrom. Baffle means ofsuitable refractory material may also be pro vided arranged in anysuitable manner for example as indicated at 34,35, 36, 37' and 38, so asto cause the hot combustion gases to passfbetween the tubes ina'circulatory manner, to the stack outlet 8.

According to my invention the lowest row of tubes 29 of the front bankof tubes 29 are continued on down below the lower drum 28 and extenddownwardly and rearwardly to a lower header 12 located outside thefurnace wiall.. The portion of the tubes 29' below the drum 28 may asshown be in a direct line with the upper portions of these tubes or theymay if desired be bent at any suitable angle to such upper portions inorder to provide the desired slope, say from to to the horizontal. Abridge wall baffle 16 comprisin for example refractory slabs, plates, or

bricks 17 is provided as before, above and supported by the lowerportions of these tubes so as to direct the combustion gases upward andeliminate the necessity for the usual fire brick bridge wall extendingvertically downward from drum 28. The lower header 12 is connected asbefore at its ends by means of pipes 13 to the upper header 14 which isconnected by short pipes 15 to the drum 28. I It will also be seen thatas before an unobstructed combustion chamber is provided extendingbetween the front and 7 rear walls of the furnace, and the baffle 16cooperates with the rear furnace wall 19 to form a pocket 20 for thecollection of soot, dust and ashes, and opening 21 and door 22 areprovided for the removal of such col- The manner of operation of thistype of boiler is well understood, including the direction of flow ofthe hot combustion gases therethrough, and the manner of operation andadvantageous features of my invention are substantially the same in thiscase as in the forms above described.

The invention comprises in any case a row of tubes located below orconstituting the lower-most row of a bank of water tubes and "havinginclined portions extending rearcated above and supported'by, andpreferably:

in direct contact. with said inclined portions of these tubes, saidinclined portions: beingthus adapted to receive heat bvradiation fromthe furnacewalls and lay conduction from said baffle meansas well asfrom the hot combustiongases themselves, and said bafilemeans beingsodisposed as to direct the combustion gases into contact with the bank ofwater tubes. Furthermore the said inclined portions of the lowermosttubes extend free of the remaining tubes of said bank, and in such aposition that a pocket is provided above and behind'said baflle means,for the collection and easy removal of deposited solid material. Also,in all the constructions shown, a large and unobstructedcombustionchamber is provided between the front and rear furnace walls,so as to provide ample space below the tubes for the complete combustionof liquid, gaseous, or powdered fuels.

I hereby disclaim so much of the subject matter of invention hereindisclosed as is disclosed also in the application with which my orginalpatent was in interference, namely, application of J. Coutant, SerialNo. 60,435, filed October 5, 1925, for Pulverized fuel combustion,claiming the French filing date of October 7, 1924.

WVh-at I claim is: v

1. In combination with a furnace having walls enclosing a combustionchamber, a

boiler having a plurality of rows of inclined" water tubes above saidcombustion chamber and connected for circulation of water there-'through, sa'id'tubes extending from a lower rear connecting vessel orheader inclinedly upwardly to a higher front connecting vessel orheader, and a single supplemental row of said tubes the same havingtheir front ends connected into said higher vessel for circulation inthe boiler, and extended first rearwardly below and parallel to theboiler tubes and then having the rear end portions thereof extendeddownwardly below the boiler from a position adjacent the remaining rowsof tubes at a substantial slant to a connecting header in a protectedposition, and such connecting header, downtake connections from thelower rear vessel feeding water to said connecting header and thereby tothe lower rear ends of such extended single row of tubes, wall elementsof refractory material associated with said slantingly extended portionsof said single row of tubes to form a closed wall wholly below theboiler and bounding the combustion chamber and exposed directly to therear ot-such: closed wall, and "such closed wall'a nd rearwallcooperating to provide a downwardly extending pocket wholly below theboiler'for collection ofvashes or solid ma- 7 'terial settling from theboiler; with means permitting discharge of material from said pocket andthere being in closedrelation to said closedwall an upward baflleextension into the boiler to. form ascending and d escending passestherein. a 2. In combination with a'furnace having I walls enclosing acombustion chamber, a boiler'having a plurality of rows of-incline'dwater tubes above said combustion chamber and connected for circulationof water there through, said tubes extending fr'om'a lower rear boilerheader inclinedly upwardly to a higher front-boiler header,;and,a singlesup,- plemental row ofsaid tubes the same having their front endsconnected into said higher header for circulation in theiboiler.and'extended first rearwardly" below and parallel to the boiler tubesand being then bent and the rear end portions thereof extended and moordiverted downwardly below the'boiler i a PQSitiOII'iIItQIIHEdlHtG theends of the remaining rows of tubes relatively steeply to aconnectingheader in a protected position, downtake connections fromthe'lower rear boiler header feedin ,water to said connect-v ingheaderand there y to the lower rear ends of such extended single row oftubes, wall elements of refractory material associated with saidsteeply-extended portions of said single row of tubes to form a closedwall wholly below the boiler and bounding the combustion chamber andexposeddirectly to the radiant heat therein; a furnace wall to the rearof suchclosed wall and such closed wall and rear, wallc'ooperating toprovide a downwardly extendingpocket wholly below theboiler forcollection of ashes or solid ma terial settling from theboiler, withmeans permitting discharge ofmaterial from said pocket, and said closedwall having an' upward bafiie extension into the boiler to formascending and descending passes therein.

' EDWARD J. FRANKLIN.

